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Many cancer drugs leave the body through the kidneys, so if your kidneys work less well the dose may need changing. The newest international guidance (2025) says to measure kidney function the same way the rest of medicine does, with the eGFR on your blood test, to use a more exact kidney test for a few drugs, and to think hard before cutting doses, because a lower dose can work less well.
No randomised trials guide anticancer dosing in kidney dysfunction, because reduced kidney function usually excludes people from trials. ADDIKD (2025), an international GRADE-and-consensus guideline from 38 working-group members covering 59 drugs, makes three general recommendations, all clinical consensus and strong: assess kidney function with eGFR by CKD-EPI, except where measured GFR is clinically necessary; use eGFR CKD-EPI to guide dosing of kidney-dependent drugs, preferring measured GFR for initial dosing of carboplatin, cisplatin and high-dose methotrexate (500 mg/m2 or more) and at extremes of body size or muscle mass, amputation or paraplegia; and use the KDIGO CKD categories to step doses. Standardised (1.73 m2) eGFR is used for every drug except carboplatin, where BSA-adjusted eGFR goes into the Calvert formula.
This departs from long practice: product information and older references use Cockcroft-Gault creatinine clearance, and BOPA (2025) still allows measured or calculated methods by local policy. ADDIKD also warns that dose cuts can harm: for cisplatin, several studies found poorer survival in people with eGFR below 60 given reduced doses, and it splits cisplatin into high and low dose at 50 mg/m2. Before deciding, weigh patient factors (hydration, performance status, liver disease, a single kidney), treatment factors (intent, an alternative regimen not dependent on the kidneys, tumour lysis risk, therapeutic drug monitoring, nephrotoxic co-medicines) and access to measured GFR. KDIGO 2024 adds that creatinine-based estimates are unreliable when kidney function is changing, and that medicines should be reviewed at transitions of care.
Why: CKD-EPI eGFR is closer to true kidney function than older estimates and is the measure the rest of medicine uses.
“We recommend the use of estimated glomerular filtration rate calculated via the Chronic Kidney Disease—Epidemiology Collaboration (eGFR CKD-EPI ) equation to guide the assessment of kidney function, except where directly measured glomerular filtration rate (GFR) is clinically necessary.”
eClinicalMedicine (Sandhu et al., ADDIKD Working Group, eviQ / Cancer Institute NSW) 2025 · clinical consensus; strong
Why: For drugs where a small error matters, or bodies where creatinine misleads, a measured GFR avoids under- or overdosing.
“Directly measured GFR is preferred to guide the initial dosing: • for a select group of anticancer drugs including, but not limited to, carboplatin, cisplatin, and methotrexate (≥500 mg/m 2 ).”
eClinicalMedicine (Sandhu et al., ADDIKD Working Group, eviQ / Cancer Institute NSW) 2025 · clinical consensus; strong
Why: Most doses are already scaled to body size; adjusting the eGFR for body size too would count it twice.
“eGFR CKD-EPI adjusted to an individual’s body surface area (BSA) is not routinely advised to guide dosing of anticancer drugs over standardised eGFR CKD-EPI , except for carboplatin.”
eClinicalMedicine (Sandhu et al., ADDIKD Working Group, eviQ / Cancer Institute NSW) 2025 · clinical consensus; strong
Why: Blood creatinine can take one to three days to rise after the kidneys are injured, so the estimate can look better than the kidneys are.
“eGFR CKD-EPI requires stable kidney function and should be performed as close as possible to the time of administering the anticancer drug(s) to ensure it is a reflective estimation of the patient’s steady state kidney function.”
eClinicalMedicine (Sandhu et al., ADDIKD Working Group, eviQ / Cancer Institute NSW) 2025 · clinical consensus; strong
Why: Common bands across all of medicine make dosing rules consistent and easier to check.
“We recommend the Kidney Disease Improving Global Outcomes (KDIGO) Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (CKD) 9 , 10 categories to guide the stepwise dose adjustment of anticancer drugs in reduced kidney function and the monitoring of drug-related adverse events.”
eClinicalMedicine (Sandhu et al., ADDIKD Working Group, eviQ / Cancer Institute NSW) 2025 · clinical consensus; strong
Why: A lower dose can mean a less effective treatment, so the decision depends on the person and the goal, not on a number alone.
“Treatment factors—treatment protocol (e.g., intent of treatment, appropriate alternative treatment protocols with similar efficacy and without drugs dependent on kidney function for dosing), risk of adverse events (e.g., tumour lysis syndrome), anticancer drug properties (e.g., pharmacokinetics, pharmacodynamics, formulation, availability of therapeutic drug monitoring), and concomitant drugs (especially with nephrotoxic potential).”
eClinicalMedicine (Sandhu et al., ADDIKD Working Group, eviQ / Cancer Institute NSW) 2025 · clinical consensus; strong
Why: Kidney function changes during treatment, and the pharmacist is the second check that the dose still fits.
“Check renal function and ensure drug doses are modified accordingly where appropriate as per drug/regimen literature.”
Why: Other medicines can damage the kidneys or raise the levels of kidney-cleared cancer drugs.
“Perform thorough medication review periodically and at transitions of care to assess adherence, continued indication, and potential drug interactions because people with CKD often have complex medication regimens and are seen by multiple specialists.”
KDIGO (Kidney International) 2024 · Practice Point 4.3.1
How care is usually carried out, read from the guidelines and standards cited. Your own team's protocol and their judgement come first; this page is for understanding it, not for doing it yourself.
ADDIKD (2025) is the only international guideline on the subject and the most recent: eGFR CKD-EPI to assess kidney function and guide dosing, measured GFR for carboplatin, cisplatin, high-dose methotrexate and unusual body composition, KDIGO categories to step doses, and a deliberate weighing of patient and treatment factors before any reduction (all clinical consensus, strong). KDIGO 2024 agrees on CKD-EPI eGFR for most drug dosing and on measured GFR or cystatin C where accuracy matters. It conflicts with product labels and older references (Krens 2019/2023, BC Cancer monographs, the Renal Drug Database), which mostly use Cockcroft-Gault creatinine clearance and sometimes different cut-offs; UK pharmacy standards (BOPA 2025) leave the method to local policy.
eClinicalMedicine (Sandhu et al., ADDIKD Working Group, eviQ / Cancer Institute NSW) 2025 · eClinicalMedicine (Sandhu et al.) 2025 · eClinicalMedicine (Sandhu et al.) 2025 · KDIGO (Kidney International) 2024 · British Oncology Pharmacy Association 2025
Where it differs: Estimates creatinine clearance by Cockcroft-Gault and applies the dose bands in the product information or a reference such as the Lancet Oncology recommendations (Krens et al.), BC Cancer monographs or the Renal Drug Database.
Evidence: ADDIKD notes Cockcroft-Gault overestimates GFR by 10 to 20% and was not validated after creatinine assays were standardised in 2010, and that existing references disagree with one another: for cisplatin some advise 25 to 50% reductions at 30 to 59 ml/min and others contraindicate it below 40. BOPA 2025 accepts measured or calculated methods (including Cockcroft-Gault) by local policy.
eClinicalMedicine (Sandhu et al., ADDIKD Working Group, eviQ / Cancer Institute NSW) 2025 · eClinicalMedicine (Sandhu et al.) 2025 · British Oncology Pharmacy Association 2025 · The Lancet Oncology (Krens et al.) 2023
Where it differs: Treats cisplatin above 50 mg/m2 (counting fractionated doses together) as high dose, and in the eGFR 45 to 59 category reduces high-dose cisplatin or considers another regimen, taking performance status and nephrotoxic co-medicines into account.
Evidence: Based on the link between high free-platinum peaks and kidney injury, and on studies showing poorer overall survival when people with eGFR below 60 were given reduced doses; low to moderate certainty in the ADDIKD tables.
eClinicalMedicine (Sandhu et al.) 2025 · eClinicalMedicine (Sandhu et al.) 2025
| Recommendation | Grade, as printed | Source |
|---|---|---|
| eGFR CKD-EPI to guide dosing of kidney-dependent anticancer drugs, except in specific situations “We recommend eGFR CKD-EPI to guide the dosing of anticancer drugs whose dose is dependent on kidney function, except in specific clinical situations or for a select group of anticancer drugs where eGFR CKD-EPI may be unsuitable.” | Evidence quality/certainty: clinical consensus; strength of recommendation: strong | eClinicalMedicine (Sandhu et al., ADDIKD Working Group, eviQ / Cancer Institute NSW) 2025 |
| Consider GFR when dosing medicines cleared by the kidneys “Consider GFR when dosing medications cleared by the kidneys.” | Practice Point 4.2.1 | KDIGO (Kidney International) 2024 |
| Validated creatinine-based eGFR equations are appropriate for drug dosing for most people “For most people and clinical settings, validated eGFR equations using SCr are appropriate for drug dosing.” | Practice Point 4.2.2 | KDIGO (Kidney International) 2024 |
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